Housing for an Optoelectronic Component, Optoelectronic Component, and Method for Producing a Housing for an Optoelectronic Component

ABSTRACT

A housing for an optoelectronic component is disclosed, having a plastic base body that has a front side with an assembly region for at least one radiation emitting or radiation detecting body, wherein the plastic base body is formed from at least one first plastic component and at least one second plastic component. The second plastic component is disposed on the front side of the plastic base body, and is formed from a material that differs from the first plastic component in at least one optical property, and forms an optically functional region of the plastic base body. Further, a method for producing a housing for an optoelectronic component and a light emitting diode component is disclosed.

This patent application claims the priority of the German patentapplication 10 2006 046 678.0 filed Sep. 29, 2006, whose disclosedcontent is hereby incorporated by reference.

TECHNICAL FIELD

The invention relates to a housing for an optoelectronic component, inparticular a surface mountable optoelectronic component, with a plasticbase body, which has a front side with a mounting region for at leastone radiation emitting or radiation detecting body. Further, theinvention relates in particular to a surface mountable optoelectroniccomponent, and a method for producing a housing for an optoelectroniccomponent.

BACKGROUND

Housings of the initially named type are described, for example, in thepatent documents EP 1022787 B1, EP 00646971 B1, WO 99/07023 A1, WO00/02262 A1 and WO 02/084749 A2. These documents describe so-calledpre-housed lead frame designs, in which a plastic base body, which isconstructed as one piece, and which is formed around the electricalconnections of the lead frame (also called electrical lead frames), isin practice manufactured from a white, reflecting thermoplasticmaterial.

However, for a series of applications, these known plastic base bodiesdo not have sufficiently satisfactory optical properties. Thus, forexample, for use in video displays, the contrast of the light spotsrelative to the surrounding housing surface is often too low.

One approach to this problem is to subsequently imprint the surface ofthe plastic base body, for example, with black pigment. Here, however,there exists the risk of color inhomogeneity in the pigment layer, andalso of insufficient color stability and/or paint flaking under theinfluence of different environmental conditions.

SUMMARY

In one aspect the present invention provides a housing of the initiallynamed type, with which desired optical properties of the housing surfacecan be obtained in an improved way. Further, a method is disclosed forproducing such a housing.

In a housing according to the invention, the plastic base body isconstructed from at least one first plastic component and at least onesecond plastic component. In this arrangement, the second plasticcomponent is located at the front side of the plastic base body, and isconstructed from a material that differs from the material of the firstplastic component in at least one optical property. The surface of thesecond plastic component forms an optically functional region of theplastic base body, generated, for example, by the addition of pigment,or filler that increases reflection. Thus, by the addition of blackpigment an increased contrast can advantageously be obtained. By theaddition of white filler, the reflectivity of the front side surface ofthe plastic base body can be advantageously increased.

In an advantageous embodiment, the plastic base body encloses electricalconnection leads of a metal lead frame, such that these extend from theassembly region to the surface of the plastic base body. This assemblyregion is disposed in a reflector-like cavity of the plastic base body.The second plastic component forms a layer along the entire front sideor along a partial area of the front side of the plastic base bodyexcept for the reflector-like cavity. In a different advantageousembodiment, this layer is drawn additionally also along at least apartial area of the lateral inner surface into the reflector-likecavity.

The thickness of the layer lies advantageously between 50 μm, inclusive,and 100 μm, inclusive.

In another advantageous embodiment, the second plastic component ismanufactured from the same plastic base material as the first plasticcomponent. Thermoplast material or duroplast material are preferablysuited as a plastic base material.

In a method according to the invention, a plastic base body is producedby means of a two-component injection-molding method (also called doubleinjection-molding method). In a first step of the process, a supportingpart of the plastic base body is preferably produced from a firstplastic component, and in a further step, an optically functional regionof the plastic base body is produced from a second plastic component.The two plastic components differ from each other in at least oneoptical property. In an alternative method, these two steps areperformed in the reverse sequence.

In the present description, and within the scope of the description ofthe exemplary embodiments, the term “injection-molding method” includesinjection molding processes and injection transfer molding processes, aswell as transfer molding processes.

In a method for producing a housing with improved contrast, for example,a pigment is mixed into the second plastic component that imparts to ita different color compared to the first plastic component. A blackpigment is particularly suited for this purpose. In another embodiment,in order to improve, for example, the reflectivity of the front side ofthe housing, the second plastic component is filled with a material thatincreases the reflectivity.

In a particularly advantageous embodiment of the method, electricalconnection leads of a metal lead frame are insert molded into the firstplastic component in such a manner that these extend from the assemblyregion for at least one radiation emitting or radiation detecting body,to the surface of the plastic base body. Subsequently, in a furtherstep, the second plastic component is formed on the first plasticcomponent. In the process, a reflector like cavity, in which theassembly region for the semiconductor body is located, is preferablyformed in the first plastic component of the plastic base body.Furthermore, the optically functional region is preferably produced fromthe same plastic base material as the remaining plastic base body. Asalready mentioned above, thermoplast material or duroplast material arepreferably suited as a plastic base material.

In an optoelectronic component according to the invention, at least onesemiconductor body that is suitable for emitting and/or detectingelectromagnetic radiation (for example, a light emitting diode, laserdiode chip, or a photodiode chip), is fastened in a plastic base body.The plastic base body has on its front side an assembly region for thesemiconductor body which is surrounded by a transparent window part, andencapsulates the semiconductor body. Electrical connection leads runfrom the assembly region to the outer surface of the plastic base body.The semiconductor body is preferably disposed on one of the electricalconnection leads. Electrical connection surfaces of the semiconductorbody are connected in an electrically conducting manner to theelectrical connection leads, for example, on the one hand, by means ofan electrical connection layer between a connection surface on the rearside and one of the electrical connection leads, and on the other hand,by means of a bond wire between a connection surface on the front sideand a second electrical connection lead. However, the semiconductor bodycan also be connected otherwise to the connection leads by usingsuitable electrical connection means. On the front side of the plasticbase body, an optically functional region is formed from a materialwhose optical properties are different from those of the remainingmaterial of the plastic base body.

The optical function area is formed by a free surface of a separateplastic component of the plastic base body, produced for example byadding pigment or reflection-increasing filler to the separate plasticcomponent. Thus, by the addition of black pigment an increased contrastcan be advantageously obtained. By the addition of white filler, thereflectivity of the front side of the plastic base body can beadvantageously increased.

The assembly region is advantageously disposed in a reflector-likecavity of the plastic base body. In a further advantageous embodiment,the separate plastic component is produced from the same plastic basematerial as the plastic component(s) which forms(form) the remainingplastic base body. Thermoplast material or duroplast material arepreferably suited as a plastic base material.

The separate plastic component forms a layer along the entire front sideor along a partial area of the front side of the plastic base bodyexcept for the reflector-like cavity. In another advantageousembodiment, this layer is additionally also drawn along at least onepartial area of the lateral inner surface into the reflector-likecavity. The thickness of the layer lies preferably between 50 μm,inclusive, and 100 μm, inclusive.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages, advantageous embodiments, and further developmentsof the invention arise from the following explanation of the exemplaryembodiments in connection with FIGS. 1 and 2. The Figures show:

FIG. 1 shows a schematic representation of a section through a firstexemplary embodiment, and

FIG. 2 shows a schematic representation of a section through a secondexemplary embodiment.

In the Figures, equivalent components or components that have the sameeffect are provided with the same reference numbers in each case. Theelements illustrated and their proportions are absolutely not to beregarded as true to scale; rather, individual elements, for example,layers and/or distances, can be represented in exaggerated size orthickness for better illustration and/or comprehension.

DETAILED DESCRIPTION

In the exemplary embodiment according to FIG. 1, a light emitting diodecomponent 1 has a light emitting diode chip 2 that is fastened on anelectrical connection lead 31 of an electrical lead frame 3, and isconnected to it in an electrically conducting manner via a contact onthe rear side. A contact on the front side of the light emitting diodechip 2 is connected to a second electrical connection lead 32 of theelectrical lead frame 3 by means of a bond wire 4.

The electrical connection leads 31, 32 are insert molded into a firstplastic component 51 of a plastic base body 5. The assembly region forthe light emitting diode chip 2 is formed in a reflector-like cavity 7on the front side 6 of the plastic base body 5. The electricalconnection leads 31, 32 extend from the bottom surface of the cavity 7through the first plastic component 51 to its side surfaces, and thereproject out beyond it. Outside of the plastic base body 5, theelectrical connection leads 31, 32 are bent towards its rear side, andin their further extent are bent onto the backside.

A layer on the front side of the plastic base body 5, whose thicknessamounts to, for example, between 50 μm and 100 μm, is formed by a secondplastic component 52, whose material differs from the material of thefirst plastic component 51 in at least one optical property. The surfaceof the second plastic component 52 forms an optically functional regionon the front side 6 of the plastic base body 5. For this purpose, thesurface has, for example, at least one pigment and/or at least onereflection increasing filler. Thus, an increase in contrast is achievedwith a black pigment. With white filler, such as titanium oxide, forexample, the reflectivity of the surface on the front side of theplastic base body 5 is increased.

The second plastic component 52 covers the entire front side 50 of thefirst plastic component 51 alongside the reflector-like cavity 7. Inexpedient embodiments (not illustrated), only a part of the front side50 can be covered by the second plastic component.

The second plastic component 52 is produced from the same plastic basematerial as the first plastic component 51, for example, fromthermoplast material or duroplast material. The plastic base materialis, for example, a material based on epoxy resin or acrylic resin, butcan also be any other material suited for plastic base bodies of theso-called premold design.

A window part 53 that is produced from, for example, a transparent ortranslucent plastic material, for example, of a reaction resin such asepoxy resin or silicon resin, is located in the reflector-like cavity 7.This window part encapsulates the light emitting diode chip 2 andserves, among other things, to protect against adverse effects due toenvironmental influences.

The plastic base body 5, the window part 53, and the lead frame 3together form the housing of the light emitting diode component 1.

The exemplary embodiment according to FIG. 2 differs from the embodimentaccording to FIG. 1, in particular, in that the layer of the secondplastic component 52 is drawn into the reflector-like cavity 7, suchthat a part of the lateral inner surface of the cavity 7 is formed by asurface of the second plastic component 52. The materials of theexemplary embodiment according to FIG. 2 correspond, for example, tothose of the exemplary embodiment according to FIG. 1, described above.

Both exemplary embodiments for the housing described above can also beused for photodiode elements. For this purpose, a photodiode chip isused in place of the light emitting diode chip.

In a method for producing a housing for a component according to theexemplary embodiments described above, a plastic base body 5 is producedby means of a two-component injection-molding method (also called doubleinjection-molding method). For this purpose, the first plastic component51 is produced in a first step as a supporting part of the plastic basebody 5. Then, in a further step, the second plastic component 52, whichhas the optically functional region of the plastic base body 5, isproduced. The two plastic components 51, 52 differ from each other, asexplained in more detail in connection with the exemplary embodimentsabove, in at least one optical property.

In the method, in the first step, the electrical connection leads 31, 32of the metal lead frame 3 are insert molded into the first plasticcomponent 51 such that these extend from the assembly region for thelight emitting diode chip 2 to the side surfaces of the plastic basebody 5. Subsequently, the second plastic component 52 is formed at thefront side of the first plastic component 51.

The invention is not limited by the description based on the exemplaryembodiments. Rather, the invention comprises each new feature, as wellas any combination of features, which includes, in particular, everycombination of features in the patent claims, even if this feature orthis combination itself is not explicitly specified in the patent claimsor exemplary embodiments.

1. A housing for an optoelectronic component, the housing comprising: aplastic base body having a front side with an assembly region formounting at least one radiation emitting or radiation detecting body,wherein the plastic base body comprises a first plastic component and asecond plastic component, wherein: the second plastic component isdisposed on the front side of the plastic base body, the second plasticcomponent is formed of a material that differs from the first plasticcomponent in at least one optical property, and the second plasticcomponent forms an optically functional region of the plastic base body.2. The housing according to claim 1, wherein the material of the secondplastic component has a pigment that imparts a different color to theoptically functional region relative to a remaining part of the plasticbase body.
 3. The housing according to claim 2, wherein the material ofthe second plastic component is colored black.
 4. The housing accordingto claim 1, wherein the material of the second plastic component isfilled with a material that increases reflectivity.
 5. The housingaccording to claim 1, wherein the plastic base body encloses electricalconnection leads of a lead frame, and the electrical connection leadsextend from the assembly region to a surface of the plastic base body.6. The housing according to claim 1, wherein the assembly region isdisposed in a reflector-like cavity of the plastic base body, and thesecond plastic component is a layer that extends along at least aportion of the front side of the plastic base body except for thereflector-like cavity.
 7. The housing according to claim 6 wherein, thelayer also runs along at least a partial area of the lateral innersurfaces of the reflector-like cavity.
 8. The housing according to claim1, wherein the optically functional region is produced from the sameplastic base material as the remaining part of the plastic base body. 9.(canceled)
 10. A light emitting diode component comprising: asemiconductor body that is suitable for emitting light, a plastic basebody that has an assembly region on a front side thereof, thesemiconductor body located at the assembly region, wherein, on the frontside, an optically functional region of the plastic base body is formedfrom a material whose optical properties are different from those ofremaining material of the plastic base body, a light transparent windowpart adjacent the assembly region, and electrical connection leads thatextend from the assembly region to an outer surface of the plastic basebody, and that are connected in an electrically conducting manner to theelectrical connection surfaces of the semiconductor body.
 11. The lightemitting diode component according to claim 10, wherein the material ofthe optically functional region comprises a pigment that imparts adifferent color to the optically functional region relative to theremaining material of the plastic base body.
 12. The light emittingdiode component according to claim 11, wherein the material of theoptically functional region is colored black.
 13. The light emittingdiode component according to claim 10, wherein the material of theoptically functional region is filled with a material that increasesreflectivity.
 14. The light emitting diode component according to claim10, wherein the plastic base body encloses the electrical connectionleads, the electrical connection leads being of a lead frame.
 15. Thelight emitting diode component according to claim 10, wherein theassembly region is disposed in a reflector-like cavity of the plasticbase body.
 16. The light emitting diode component according to claim 10,wherein the optically functional region is produced from the sameplastic base material as the remaining material of the plastic basebody.
 17. (canceled)
 18. A method for producing a housing for anoptoelectronic component, the method comprising: forming a plastic basebody by means of a two-component injection method that comprises: in afirst step, forming a supporting part of the plastic base body from afirst plastic component, and in a further step, forming an opticallyfunctional region of the plastic base body from a second plasticcomponent that differs from the first plastic component in at least oneoptical property.
 19. The method according to claim 18, wherein apigment is mixed into the second plastic component that imparts adifferent color to the second plastic component relative to the firstplastic component.
 20. The method according to claim 19, wherein thesecond plastic component is colored black.
 21. The method according toclaim 18, wherein the second plastic component is filled with a materialthat increases reflectivity.
 22. The method according to claim 18,further comprising insert-molding electrical connection leads of a metallead frame to the first plastic component such that said leads extendfrom an assembly region for at least one radiation emitting or radiationdetecting body to a surface of the plastic base body, wherein, thesecond plastic component is formed on the first plastic component in asubsequent step.
 23. The method according to claim 22, wherein areflector-like cavity is formed in the first plastic component of theplastic base body, the assembly region being disposed in the cavity. 24.The method according to claim 18, wherein the optically functionalregion is produced from the same plastic base material as the supportingpart of the plastic base body.
 25. The method according to claim 18,wherein the optically functional region and the supporting part of theplastic base body comprise thermoplast material or duroplast material.